Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description adds real context beyond that — lobby ordering of results, the returned per-game fields including a 'site-wide jackpot flag', and aggregate studio/badge counts. It omits rate limits and does not mention that the region/lobby constrains which categories exist, but the added behavior is substantial.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the action and result shape, then usage and prerequisites. The first sentence is dense with enumerated return fields, but each clause carries information an agent needs; nothing is filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return values need not be described, yet the description still names the key fields and the category-count aggregates. Prerequisite chain (categories → slug → this tool) is spelled out and pagination is implied by limit/offset. The one gap is that the region/lobby parameter, which can invalidate a category, goes unmentioned in the prose.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents every parameter including defaults and examples. The description only restates the parameter names ('accepts q, provider, badge, limit and offset') and notes where the category slug comes from, adding no syntax or filtering semantics beyond the schema. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('List the games of a FanDuel Casino category'), plus the ordering (lobby order) and the fields returned (slug, name, studio, badge, jackpot flag). That level of specificity easily distinguishes it from the sibling fanduel_casino_categories (which supplies the slug) and fanduel_casino_game (single-game detail) without opening either schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear use case ('browse or search the casino catalog (about 3,800 games in all-games)') and the hard prerequisite ('needs a category slug from fanduel_casino_categories'). It does not name an explicit when-not or say where to go for a single game's full detail, so it stops short of full alternative routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.